Bug 2524476 (CVE-2026-74741)

Summary: CVE-2026-74741 kernel: net: ngbe: fix NULL pointer dereference in non-MSI-X interrupt enabling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's ngbe network driver. In systems configured for non-MSI-X interrupt handling, such as legacy INTx or single MSI modes, a missing initialization of a pointer can lead to a NULL pointer dereference. This vulnerability can cause the system to crash, resulting in a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-26 14:58:24 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: ngbe: fix NULL pointer dereference in non-MSI-X interrupt enabling

In non-MSI-X mode (such as legacy INTx or single MSI), wx->msix_entry is
not allocated or initialized. Calling NGBE_INTR_MISC(wx) dereferences
wx->msix_entry->entry, leading to a NULL pointer dereference crash.

This issue was introduced by fixing the IRQ vector when the number of
VFs is 7. Fix the issue by explicitly checking `pdev->msix_enabled` to
determine the correct vector index.

Additionally, as a side fix, set the interrupt mask to BIT(0) for the
non-MSI-X fallback. In MSI/INTx mode, the MISC and queue interrupts
share vector 0, and the WX_PX_MISC_IVAR register is only valid in the
MSI-X case. Thus, BIT(0) is the correct mask for the miscellaneous cause
when MSI-X is disabled.
Comment 1 gkamathe 2026-08-27 10:55:46 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026082657-CVE-2026-74741-6e2b@gregkh/T